I'm wondering what should happen when you load a squad that has a ship using a particular slot and the current version of the rules has removed the slot from said ship?

I'm curious what should happen as well as if this has been tested.

I think it would be nice if the squad still loaded 'intact' but you see an alert symbol somewhere telling you the squad is not legal (whether it be due to points changes or slots). Then you can hover over the alert to find out what errors have been found. To fix the slot issue, you pick the slot that has an upgrade and choose no upgrade. At this point, the slot can disappear. I think this is nice as it lets the user control loss of data (removal of the upgrade) in case they decide they want to preserve the squad for playing their own legacy format or just to check what is changing before updating it (as it could drastically change the relevance of the squad).